Pregnancy outcome following exposure to shortwaves among female physiotherapists in Israel

Background The findings of the few epidemiological studies on the possible association between shortwave diathermy use by pregnant physiotherapists and adverse pregnancy outcome are inconsistent. We investigated such an association among physiotherapists in Israel. Methods Individualized data on exposure to shortwaves, ultrasound, and heavy lifting were collected by questionnaires and telephone interviews. Results The 434 studied women included 930 pregnancies: 175 ended in spontaneous abortions, 45 had fetal malformations, 47 were delivered prematurely, and 33 infants had low birth weight. The remaining 630 normal pregnancies comprised the control group. Univariate analysis showed that exposure to shortwaves was associated with a significantly increased odds ratio (O.R.) for congenital malformations (O.R. 2.24, CI 1.27-4.83, P =.006) and low birth weight (O.R. 2.99, CI 1.32-6.79, P =.006). This effect increased in a dose-related manner. After controlling for potential confounding variables, only low birth weight reached statistical significance (O.R. 2.75, CI 1.07-7.04, P =.03). From the potentially confounding variables tested, febrile disease during pregnancy was found to be significantly associated with low birth weight (O.R. 3.37, CI 1.38-8.25, P =.01). Conclusions The findings of our study suggest that shortwaves have potentially harmful effects on pregnancy outcome, specifically low birth weight.